
3-120. Hilda was simplifying some numerical expressions and made each of the following
sequences of calculations. Name the mathematical property, operation, or idea that justifies how
Hilda went from each step to the next step.
a.
b.
3-122. Refer to the diagram at right to answer the questions below.
a.
Copy the diagram and add two tiles so that the result is a value of –2. You can add positive
and/or negative tiles. Show the tiles you added to get this answer.
b. Copy the diagram again, but this time remove four tiles (again positives and/or negatives) so
that the result is a value of 2. Show the tiles you removed to get this answer.
3-123. Copy and complete each of the Diamond Problems below. The pattern used
in the Diamond Problems is shown at right.
3-125. Solve the following problems without paper or pencil. Just write the answer but be
ready to explain your thinking.
3-128. Find each product. Express your answer as both a fraction and a decimal.